Alkyltrimethylammonium Bromides Research Articles

Photophysical Response of Propranolol in Biomimetic Micellar Media of Alkyltrimethylammonium Bromide Surfactants: Effect of pH and Alkyl Chain Length.

The photophysical behavior of a β-blocker drug propranolol (PPL) in micellar environments, formed by alkyltrimethylammonium bromide surfactants viz.; Cetyltrimethylammonium bromide (CTAB), Tetradecyltrimethylammonium bromide (TTAB), and Dodecyltrimethylammonium bromide (DTAB), has been investigated through fluorescence and UV-visible spectroscopic techniques at pH levels of 3.5, 7.4, and 10.4. The impact of pH on the critical micelle concentration (cmc) and micropolarity of micelles were assessed using pyrene as a photophysical probe. The cmc values were found to be lower at pH 10.4 compared to pH 7.4 and pH 3.5. Fluorescence emission intensities of PPL at 323nm, 338nm, and 352nm were significantly influenced by pH, hydrophobic alkyl chain length of surfactants, and their concentrations. Quenching experiments with Cetylpyridinium chloride (CpCl) indicated the localization of charged and uncharged forms of PPL within micelles, with quenching constant (Ksv) values dependent on alkyl chain length and pH. At pH < pKa, PPL is positioned near the Stern layer, whereas at pH 10.4, its naphthalene moiety resides near the hydrophobic micellar core. UV spectroscopy showed that the charged form of PPL interacted with micelles only above cmc, while the neutral form interacted even below the cmc. Density Functional Theory (DFT) reveals the HOMO of the surfactants to be localized on the hydrocarbon chains, and the LUMO localized around the quaternary ammonium unit. Upon complexation with PPL, both HOMO and LUMO shifted to the drug, thereby decreasing energy levels. The findings are explained based on weak noncovalent interactions, further supported and analyzed through Reduced Density Gradient (RDG) and Noncovalent Interaction (NCI) methods, confirming synergistic non-covalent interactions in surfactant-PPL complexes.

Effect of hydrocarbon chain length of alkyl trimethyl ammonium bromide on corrosion inhibition of stainless steel in sulfuric acid

Effect of hydrocarbon chain length of alkyl trimethyl ammonium bromide on corrosion inhibition of stainless steel in sulfuric acid

Influence of titanium dioxide nanotubes with alkyl ammonium alkyl bromide on the physicochemical properties and adhesion of experimental adhesive resins to dentin

ObjectiveThis study evaluated the effect of the incorporation of titanium dioxide nanotubes with alkyl trimethyl ammonium bromide (ntTiO2/ATAB) into experimental adhesive resins on their physicochemical properties and adhesion to dentin. Materials & methodsThe experimental adhesive resins were formulated with 66.66 wt% Bis-GMA and 33.33 wt% HEMA, photoinitiator with addition of ntTiO2/ATAB (1:1) in different concentrations: G1%, G2.5%, and G5%. One groups with no ntTiO2/ATAB addition was used as control (G0%). An optical tensiometer was used to analyze the contact angle (COA) by the sessile drop method (distilled water and α-bromonaphthalene) (n = 5), while the surface free energy (SFE) was calculated using Owens-Wendt-Rabel-Kaelble method. Flexural strength (FS) test (three-point bending) of polymerized adhesive samples was performed according to ISO 4049:2019 (n = 10) after 24 h or one year of water storage at 37 °C, as well as for the microtensile bond strength (μTBS) test, in which a commercial adhesive (GSBMP) was also used as control (n = 10). The adhesive-dentin interfaces were evaluated by scanning electron microscopy and X-ray spectrometry (n = 5). Data were analyzed by one-way (COA and SFE), two-way (FLE and μTBS) ANOVA and Tukey's test (α = 0.05). ResultsG5% showed the highest COA with nonpolar liquid and higher SFE than G0%. The G5% showed decreased FS compared to G0%. The μTBS of both controls (G0% and GSBMP) decreased after one year. TiO2/ATAB-containing adhesives to dentin showed no significant decrease after one year. All adhesives formed hybrid layer and the resin tags inside the dentinal tubules. ConclusionsThe incorporation of 1 and 2.5% of ntTiO2/ATAB into experimental adhesive resins did not impar the SFE. After one year, any concentration of ntTiO2/ATAB reduced the FS compared with control, but did not impair the μTBS.

Cationic micelles in deep eutectic solvents: effects of solvent composition.

Deep eutectic solvents (DES) are mixtures of hydrogen bond donors and acceptors that form strongly hydrogen-bonded room temperature liquids. Changing the H-bonding components and their ratios can alter the physicochemical properties of deep eutectic solvents. Recent studies have shown p-toluenesulfonic acid (pTSA) forms room temperature liquids with choline chloride (ChCl) at different molar ratios: 1 : 1, 1 : 2 and 2 : 1 [Rodriguez Rodriguez et al., ACS Sustain. Chem. Eng., 2019, 7(4), 3940]. They also showed that the composition affects the physical properties of these liquids and their ability to dissolve metal oxides. In this work we evaluate the solubility and self-assembly of cationic surfactants alkyltrimethyl ammonium bromides (CnTAB) in these pTSA/ChCl based liquids. CnTABs are insoluble in 1pTSA : 2ChCl, whereas in 1pTSA : 1ChCl and 2pTSA : 1ChCl they form micelles. We characterise CnTAB (n = 12, 14, 16) micelles using small angle neutron scattering and also look at interaction of water with the micelles. These studies help determine the interaction of DES components with the surfactant and the influence of varying pTSA and water ratios on these interactions. This provides potential for controlled surfactant templating and for tuning rheology modification in such systems.

The role of hydrophobic interactions in the molten globule state of globular protein modulated by surfactants.

In order to highlight the role of hydrophobic interactions in the molten globule (MG) state of globular protein modulated by surfactants, the interactions of bovine α-lactalbumin (α-LA) with alkyl trimethylammonium bromides (CnTAB, n=10, 12, 14, and 16) have been studied by experimental and theoretical techniques. Isothermal titration calorimetry (ITC) showed that the enthalpy changes (ΔH) and area of the enthalpogram increased with increasing the chain length of CnTAB. The result of fluorescence, circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) spectrum suggested that C10TAB and C12TAB unfolded α-LA partially, C14TAB reconstructed protein with a native-like secondary structure content, and C16TAB induced an MG state α-LA. The SAXS results confirmed that the tertiary structure of α-LA was disrupted by C16TAB forming an MG state complex with a micelle-like structure even at the surfactants concentrations below CMC. As indicated by MD results, the β-domain and unstructured region(s) were involved in the MG state α-LA modulated by CnTAB. This work not only provides molecular insights into the role of hydrophobic interactions in the MG state of a globular protein but also helps understand the mechanism of preparing α-LA based biomacromolecule modulated by hydrophobic interactions.

Micellization of dodecyldimethyl-N-2-phenoxyethylammonium bromide (domiphen) in aqueous solution. Comparison with other alkyl ammonium surfactants

Dodecyldimethyl-N-2-phenoxyethylammonium bromide (domiphen) is a quaternary ammonium salt which has been used in oral hygiene long time ago. The published studies on its characterization as surfactant evidence several contradictory results. In this paper, measurements of surface tension, conductimetry, fluorescence and mainly isotermal titration calorimetry (ITC) have been performed at different temperatures. The enthalpy of demicellization, ΔHdemo, varies linearly with temperature in the interval 15–45 °C, from which a value of 704 ± 39 J mol−1K−1 in water has been determined for the change of heat capacity, ΔCP,demo. The obtained results are compared with published values for alkyltrimethylammonium bromides with different alkyl chain lengths (CnTAB). For instance, its critical micelle concentration, cmc, is almost ten times lower than that of C12TAB. The substitution of one methyl group by the phenoxyethyl has a strong influence on the behavior of domiphen making it equivalent to a CnTAB surfactant with n = 15–19 methylene groups, the number depending on the studied property. From ITC an average aggregation number of 45 ± 3 is obtained in good agreement with the one from fluorescence quenching of pyrene equal to 44.5–47.6. From the analysis of specific conductivity, the fraction of bound counterions to micelles was obtained, the values linearly decreasing with temperature. Below cmc domiphen behaves as a strong 1:1 electrolyte without association of monomers. Other themodynamic parameters have also been obtained. The fjord and reef hydration models are used to propose a structure for domiphen micelles.

Effect of hydrophilic atenolol and lipophilic propranolol β-blockers on the surface and bulk aggregation of quaternary ammonium bromide surfactants: A comparative study

The variations in the surface and bulk properties of alkyltrimethylammonium bromide (ATAB) surfactants (C12 to C16) in presence of a hydrophilic β-blocker drug atenolol (ATL) and a lipophilic β-blocker drug propranolol (PPL), have been investigated using three independent techniques, viz; electrical conductivity, surface tension and cyclic voltammetry. Electrical conductivity measurement indicates that both ATL and PPL at low concentrations of 0.5 mM and 1.0 mM brings about almost equal changes to the critical micelliastion concentration of all ATAB surfactants. However, at higher concentrations (3 mM to 10 mM), PPL seems to be more effective, than ATL, in reducing the cmc and hence favouring micellization. Various interfacial parameters at the air–water interface have been determined through the measurements of surface tension of the surfactants in varying concentrations of ATL and PPL ranging from 0.5 mM to 10 mM. The thermodynamic parameters of micellization are evaluated from the temperature dependence of cmc. The variation of Gibbs energy with temperature is small while large changes in enthalpy and entropy of micellization are observed in the temperature range studied. The effect of TTAB on the electrolytic solutions of ATL and PPL on the voltametric response of glassy carbon electrode (GCE) was examined. TTAB enhanced the current signal of ATL while opposite effect was observed for PPL. The experimental results have been analysed in terms of the difference in the hydrophobicities of the two β-blocker drug molecules.

Friday 30th September - 10:30 - 12:0051 - Effects of titanium dioxide nanotubes with alkyltrimethylammonium bromide into adhesives

Friday 30th September - 10:30 - 12:0051 - Effects of titanium dioxide nanotubes with alkyltrimethylammonium bromide into adhesives

Determination of hydrophobicity and hydrophilicity ratio in the synergistic effect between cationic surfactants using coarse-grained MD simulation

Using computational tools to study micelle formation allows us to gain a better understanding of various physical phenomena that cannot be measured experimentally. The synergistic effect of mixing different surfactants is one challenging question and the composition or morphology of mixed micelles is another. In this work, coarse-grained (CG) molecular dynamics (MD) simulations were used to study the self-assembly of three types of alkyl trimethylammonium bromide (TAB) surfactants, individually and in the binary mixtures, as well as their synergism during mixing. First, the radius of gyration, eccentricity, and degree of counterion dissociation of the micelles for pure solutions provided valuable data on the morphology of the TAB micelles and almost correlated with the experimental results based on the alkyl chain length. Then, the binary mixtures of the combination of two different TAB surfactants were simulated at different mole fractions. At a specific concentration, mixing two different surfactants from a similar family with different alkyl chain lengths showed the synergistic effect that improved micellization. When the difference between the two kinds of surfactants is high, the surfactant with fewer numbers acts as the core for micelle formation whereas, at equal or almost equal concentrations, a longer-tail surfactant acts as a core. According to simulation and the interaction parameter (βm), electrostatic interaction is repulsive because of similar charges, while van der Waals interaction is attractive because of the hydrophobic alkyl chain. A substantial synergistic effect was observed with the mixed micelle comprised of surfactants with longer and similar chain lengths. These findings revealed molecular-level information about TAB surfactants with mixing and are expected to trigger further research because of a great deal of interest in these surfactants and mixing in different applications.

Direct Resolution of the Interactions of a Hydrocarbon Gas with Adsorbed Surfactant Monolayers at the Water/Air Interface Using Neutron Reflectometry

We have directly resolved in the present work the interfacial composition during and after the interactions of a saturated atmosphere of oil vapor with soluble surfactant solutions at a planar water/air interface for the first time. Experiments were conducted on interactions of hexane vapor with solutions of alkyltrimethylammonium bromides and sodium dodecyl sulfate to observe the balance between cooperativity and competition of the components at the interface. In all cases, hexane adsorption was strongly enhanced by the presence of the surfactant, even at bulk surfactant concentrations four orders of magnitude below the critical micelle concentration. Cooperativity of the surfactant adsorption was observed only for sodium dodecyl sulfate at intermediate bulk concentrations, yet for all four systems, competition set in at higher concentrations, as hexane adsorption reduced the surfactant surface excess. The data fully supported the complete removal of hexane from the interface following venting of the system to remove the saturated atmosphere of oil vapor. These results help to identify future experiments that would elaborate and could explain the cooperativity of surfactant adsorption, such as on cationic surfactants with short alkyl chains and a broader series of anionic surfactants. This work holds relevance for oil recovery applications with foam, where there is a gas phase saturated with oil vapor.

Photophysical properties and aggregation behavior of diethylene glycol substituted pyropheophorbide-a in cationic surfactant solutions

The aggregation behavior of a novel amphiphilic photosensitizer - pyropheophorbide-[Formula: see text] 17-diethylene glycol ester 1 was studied in aqueous and aqueous-organic mixtures by means of steady-state absorption and fluorescence emission spectroscopy. The formation of [Formula: see text]-aggregates with a bathochromic shift of the absorption bands, weak fluorescence and resonance enhancement of the light scattering was observed in the mixed water-organic solvents. Solubilization studies in micellar cationic surfactant solutions of alkyl trimethylammonium bromides (C[Formula: see text]TAB) and alkyl triphenylphosphonium bromides (C[Formula: see text]TPPB) resulted in the most effective stabilization of the fluorescent monomolecular form of 1 in C[Formula: see text]TPPB micelles. It was shown that [Formula: see text]-aggregate formation in submicellar surfactant solutions is the initial stage of the solubilization process, which significantly increases in phosphate buffer medium at pH 7.4. Fluorescence lifetime ([Formula: see text] of 1 in DMSO was found to be 7.4 ns, fluorescence quantum yield - 34% and singlet oxygen quantum yield - 62%. The results obtained indicate the need for further studies of compound 1 solubilized in C[Formula: see text]TPPB micelles as the most promising prototype of the drug formulation for mitochondria-targeted photodynamic therapy of cancer.

Alkyl trimethyl ammonium bromide for the formulation of antibacterial orthodontic resins.

This study aimed at formulating antibacterial orthodontic resins containing alkyl trimethyl ammonium bromide (ATAB) and evaluating their physicochemical and biological properties. The chemical composition and microstructure ofATAB was characterizedthrough FTIR and SEM, respectively. Experimental orthodontic BisGMA/TEGDMA-based resins were formulated, and the ATAB filler was incorporated at 1wt%, 5wt%, and 10wt%, along with colloidal silica (5wt%). The degree of conversion, softening in solvent, and flexural strength of the experimentalresins were analyzed. Biological properties were also assessed through cytotoxicity and antibacterial analyses. The incorporation of ATAB, due to the presence of ⎯N+(CH3)3 alkyl groups, had no adverse effect on the degree of conversion of the resins (p > 0.05). The %ΔKHN values at 5wt% and 10wt% were comparable to those of the control group, while the flexural strength was reduced at all concentrations of ATAB. The viability of the gingival fibroblast was reduced with the addition of ATAB (p < 0.05). The viability of biofilm and planktonic bacteria was reduced when ATAB was incorporated at 5wt% and 10wt%. The addition of ATAB at 5wt% resulted suitable for the formulation of orthodontic resins with the ability to control the biofilm formation and planktonic activity of S.mutans, without jeopardizing some specific physicochemical properties. White spot lesions in orthodontic patients may be controlled by preventive treatments. Non-patient-dependent strategies, such as the use of orthodontic resins containing ATAB, may avoid accumulation of bacteria, especially in those areas surrounding orthodontic appliances.

Structure effect in the demulsification performance of cationic surfactants

In this study, various cationic surfactants and MgO nanoparticles were used for dehydration of crude oil. The results of bottle tests exhibited that in demulsification of crude oil in the serious of alkyl trimethyl ammonium bromide homologs (CnTAB, n = 12, 14, and 16) with the increase of alkyl chain length, the optimum concentration level decreased and speed of dehydration decreased. Also, for surveying the role of head group, two cetrimonium bromide and cetylpyridinium bromide surfactants were used. Evaluation of the counter ion effect indicated in the high concentration of surfactants the counter ion can greatly influence the demulsification performance. Moreover, for enhancing demulsification, MgO nanoparticles were mixed with cetrimonium bromide (CTAB) surfactant. The mixture of MgO nanoparticles and CTAB (in ratio 1:3) could dehydrate crude oil in 300s. For better understanding of asphaltene-demulsifier interaction, was used the quantum calculation. The results demonstrate MgO interacts with asphaltene strongly.As well as the result of asphaltene adsorption on MgO indicate the asphaltene adsorption flow from Freundlich model. Finally, the interaction energy between surfactants or MgO and asphaltene were estimated by quantum calculation.

Cosurfactants for controlling the surface properties of diluted solutions: Interplay with bulk rheology of concentrated solutions

The effect of the fatty alcohols (CnOH), fatty acids (CnAc), alkyltrimethyl ammonium bromides (CnTAB), alkyl sulfates (CnSO4Na) and alkyl acetates (CnAcet), with n varied between 6 and 12 C-atoms, on the surface properties of 0.5 wt% mixed solutions of sodium laurylether sulfate (SLES) and cocoamidopropyl betaine (CAPB) was studied. It was shown that the equilibrium surface tension decreases with increasing the cosurfactant chain-length. For example, the addition of C12OH to SLES+CAPB solution decreases its surface tension from 29 down to 22 mN/m. Both the dynamic surface tension and the characteristic adsorption time pass through a deep minimum when cationic or nonionic cosurfactants with 8 or 10 C-atoms are added. The minimum is particularly deep for nonionic surfactants with small head group (acids and alcohols) which destabilize the micelles and increase the rate of surfactant adsorption. The addition of anionic cosurfactants does not change the dynamic and equilibrium surface tensions of SLES+CAPB system. A strong correlation between the dynamic surface tension of diluted surfactant solutions (0.5 wt%) and the viscosity of the respective concentrated solutions (10 wt%) is established and explained for nonionic cosurfactants.

The Processes of Crown-Substituted Magnesium Phthalocyaninate Dissolution in Water in the Presence of Alkyltrimethylammonium Bromides

The Processes of Crown-Substituted Magnesium Phthalocyaninate Dissolution in Water in the Presence of Alkyltrimethylammonium Bromides

Vesicle formation of single-tailed amphiphilic alkyltrimethylammonium bromides in water induced by dehydration-rehydration.

We recently found that rough glass surfaces (RGSs) can in situ mediate the micelle-to-vesicle transition in single-component solutions of simple single-tailed amphiphiles (STAs), but only result in a relatively small number of vesicles coexisting with a large number of micelles. In the current work, a dehydration-rehydration (DHRH) method was used to induce the formation of vesicles in the single-component aqueous solutions of alkyltrimethylammonium bromides (CnTABs, n = 12, 14, and 16), a kind of typical cationic STAs. That is, a CnTAB micelle solution dropped on smooth glass surfaces (SGSs) was first dried, and the dried CnTAB aggregates were then rehydrated in a monomer solution of CnTAB. A large population of vesicles and even pure vesicle (or vesicle-dominated) systems were obtained, indicating that the DHRH process could more effectively induce the formation of STA vesicles than RGS in situ mediation. The so-obtained vesicles were characterized using DLS, FF-/cryo-TEM, AFM, SAXS, and fluorescence techniques, and their stability was determined. In addition, the effects of the conditions of DHRH and the chain length of CnTABs on the vesicle formation were examined. It was demonstrated that the vesicles can be formed as long as the concentrations of CnTABs in the rehydrated systems are higher than their critical micelle concentrations. The size and wall thickness of vesicles increase with an increase in chain length. A possible mechanism for the DHRH-induced vesicle formation is proposed: bilayer sheets are formed on SGSs during dehydration, and then detached from the SGSs to form vesicles during rehydration. A highly interdigitated structure of alkyl chains between two leaflets was identified in the bilayers, which probably is the origin of the formation and stability of STA vesicles.

Physico-chemical and spectroscopic investigation of flavonoid dispersed C n TAB micelles.

In this study, kaempferol (0.2 m/mmol kg−1) dispersed cationic surfactant micelles were prepared as a function of alkyltrimethylammonium bromide (CnTAB) hydrophobicity (C = 12 to C = 16). The dispersion study of kaempferol in different CnTAB, i.e. dodecyltrimethylammonium bromide (C = 12), tetradecyltrimethylammonium bromide (C = 14) and hexadecyltrimethylammonium bromide (C = 16), was conducted with the physico-chemical properties of density, sound velocity, viscosity, surface tension, isentropic compressibility, acoustic impedance, surface excess concentration and area occupied per molecule and thermodynamic parameters Gibbs free energy, enthalpy and activation energy measured at 298.15 K. These properties were measured with varying concentration of CnTAB from 0.0260 to 0.0305 mol kg−1 in a 10% (w/w) aqueous dimethyl sulfoxide solvent system. The variations in these measured properties have been used to infer the kaempferol dispersion stability via hydrophobic–hydrophilic, hydrophilic–hydrophilic, van der Waals, hydrogen bonding and other non-covalent interactions.

Transition from antagonistic to synergistic interaction in mixed micellar system by increase in alkyl chain length of alkyl trimethylammonium bromide

Herein, the electrical conductivity technique used to measure the critical micelle concentration (cmc) for pure cationic surfactants (Dodecyl/cetyltrimethylammonium bromides) and phenothiazine drug (Promethazine hydrochloride), as well as their different mole fractions in 10−3 ​mol/kg 1-methyl-3-octylimidazolium chloride (C8mim.Cl) at different temperatures. By using the cmc values the regular solution theory used to evaluate the micellar mole fraction for DTAB/CTAB-PMT mixed systems. The clint's model used to calculate the ideal critical micelle concentration (cmc∗) that helps to evaluate the ideal micellar mole fraction for studied mixed systems, both explain the deviation from ideality. In addition, interaction parameter βm helps to confirm the nature of interaction (either antagonistic or synergistic) for the studied systems. The calculated parameters confirm a transition in the binding nature from antagonistic to synergistic with the increase in alkyl chain length of cationic surfactant i.e., component of the binary mixed system. The ease of micellization for the studied systems discussed by the standard Gibb's energy of micellization (ΔGm0), as well as the standard enthalpy and standard entropy of micellization were (ΔHm0) and (ΔSm0), respectively to discuss the stability of the studied systems.

Analysis and Quantification of Alkyl (C12-22) Trimethyl Ammonium Chloride Content in Cosmetics: Regulatory Compliance Gap Analysis

Background: Exceeding the recommended Alkyl (C12-22) trimethyl ammonium bromide and chloride levels in cosmetics and personal care products is a serious health threat. Objectives: To quantify and investigate Cetrimonium chloride and Behentrimonium chloride in cosmetics and personal care products in the UAE market to gauge whether or not they adhered to requirements for safety and health. Methods: A total of 164 cosmetics products were collected and analyzed in this study. The gas chromatography–mass spectrometry (GC–MS) method was developed and validated for the determination of Cetrimonium chloride and Behentrimonium chloride surfactants in cosmetics products. With each product, Cetrimonium chloride and Behentrimonium chloride (%) were calculated. To test cross-group differences in Cetrimonium chloride and Behentrimonium chloride (%), Kruskal–Wallis test was applied. Results: Of the 125 tested cosmetics and personal care products, five (4%) exceeded the recommended Cetrimonium chloride level in rinse-off hair products (2.5%), 10 (8%) exceeded the recommended Cetrimonium chloride level in leave-on hair products (1%), and 24 (61.5%) exceeded the recommended Cetrimonium chloride level used as a preservative in cosmetics products. Moreover, of the 125 tested cosmetics and personal care products, 21 (53.8%) exceeded the recommended Behentrimonium chloride level used as preservatives in cosmetics products. Conclusions: Although several structures for cosmetics quality and control across the globe are fairly comprehensive and intricate, there is a need to make them more rigorous to apply compliance with GMP and ensure regulatory control. Doing so would help enhance the inspection and regulation of cosmetics containing Behentrimonium chloride/Cetrimonium chloride preservatives. Furthermore, there is a dire need to establish a unified cosmetovigilance worldwide.

Peculiarities of alkylamidopropyldimethylbenzylammonium (Miramistin) in the relationship to lysozyme in comparison with quaternary ammonium surfactants: Coadsorption at the interfaces, enzymatic activity and molecular docking

Benzyldimethyl[3-[(1-oxotetradecyl)amino]propyl]ammonium chloride available as Miramistin is an effective antimicrobial agent, but its colloidal properties and interaction with proteins are not studied well. In present work we compared Miramistin with series of alkyltrimethylammonium bromides (DTAB, TTAB and CTAB) in the relationship to lysozyme. Complex analysis including coadsorption at the aqueous-air and aqueous-organic liquid interfaces, protein intrinsic fluorescence and enzymatic activity of lysozyme in the presence of surfactants was performed. By means of radiochemical and spectroscopic methods we have shown that cationic surfactants form complexes with lysozyme at the interfaces as well as in the bulk of the solution. Lysozyme and cationic surfactants replace each other in the adsorption layer. Miramistin binds to lysozyme surface as well as to its active site with high efficiency like surfactant with short hydrocarbon moiety (DTAB), nevertheless, it possesses low value of critical micelle concentration like CTAB. Quaternary ammonium surfactants increase enzymatic activity of lysozyme: Miramistin enhances the activity intensively then all alkyltrimethylammonium bromides. This result is explained by docking results indicated that in the case of Miramistin Asp52 residue does not form bond with the ligand unlike the cases with other alkyltrimethylammonium bromides.